Neil, there is a sub-forum for telescope making here on IIS, and also on Cloudy Nights in the US.
As far as Dob building goes I hope you have a copy of David Kriege's excellent book on the subject.
http://www.bintel.com.au/Accessories...oductview.aspx
Look here: ATM and DIY Projects on IIS:
http://www.iceinspace.com.au/forum/f...splay.php?f=17
and here on Cloudy Nights:
http://www.cloudynights.com/forum/70...and-diy-forum/